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It is often said that heavier cars are inherently safer than lighter ones. However, when all cars are built with steel, larger size necessarily implies greater weight, so it is unclear whether the improved safety correlates to the weight or size of the vehicle. Using a publicly available computer model of the Ford Taurus, it was thought that this perception could be tested. The existing steel model, with the addition of a Hybrid III dummy and driver side airbag, was validated against actual crash test data. The structure was converted to aluminum, structural stiffness was calculated, and the steel and aluminum crash simulation results were compared. The aluminum model, utilizing monocoque sheet structure, weld bonded joining, and tailor welded blanks, weighed 200 kg less than the steel model and performed as well.

Failure Mode Verification Testing (FMVT) is a highly accelerated test method that uncovers design weaknesses in mechanical products. The goal of the technique is to uncover design inherent failure modes in a very short amount of time by applying a broad range of stress patterns at elevated levels. The FMVT technique is an application of the Highly Accelerated Life Test (HALT) methodology. HALT has been used in aerospace and electronics industry for many years.3 FMVT provides for a measure of the design's maturity but does not determine the life expectancy or reliability of a product. FMVT has been used on mechanical systems by adapting the traditional HALT frequency ranges, and other stress sources to mechanical systems. FMVT has been successfully applied to several automotive mechanical products.

This paper deals with new concepts for automotive glazing applications, with reference to weight reduction, improved security, and enhanced robustness: Laminated sidelights and asymmetrical windshields are considered. Main advantages are reviewed. Best designs are proposed considering the main functionalities of both products, particularly the mechanical properties required for automotive glazing.

A better understanding is needed of the electrostatic rotating bell (ESRB) application of metallic basecoat paint to automobile exteriors in order to exploit their high transfer efficiency without compromising the coating quality. This paper presents the initial results from experimental investigation of sprays from an ESRB which is designed to apply water-borne paint. Water was used as paint surrogate for simplicity. The atomization and transport regions of the spray were investigated using laser light sheet visualizations and phase Doppler particle analyzer (PDPA). The experiments were conducted at varying levels of the three important operating parameters: liquid flow rate, shaping-air flow rate, and bellcup rotational speed. The results show that bellcup speed dominates atomization, but liquid and shaping-air flow rate settings significantly influence the spray structure. The visualization images showed that the atomization occurs in ligament breakup regime.

A finite-element (FE) based method for numerically predicting fatigue life of MAG-welded thin-sheet structures has been established and tested. The method uses nodal forces and moments calculated along the weld line, together with an analytical expression for the structural stress at the weld toe. The calculated stress is used together with an experimentally determined Wöhler, or S-N, curve. A “stiff” welded joint with structural stress dominated by membrane forces is found to have a steeper S-N curve than a “flexible” joint with structural stress dominated by bending moment. All test results were seen to lie close to one of two different S-N curves. The proportion of bending stress over total structural stress could be used for choosing the appropriate S-N curve.

VSAERO, a subsonic panel method, has grown from a maximum of 1000 panels (unknowns) to the routine use of 10000 panels to model aircraft such as an MD-11 with deployed slats and flaps. The increasing complexity required improvements in user-friendliness including: a robust flow solver; graphical interfaces to generate input and visualize output; algorithms which produce correct results (within the assumptions of potential flow); diagnostics to signal when the assumptions are violated; increased versatility with body wakes and jet exhausts; and multiple ways of generating a model.

Modelling and simulation is of crucial importance for the understanding of system dynamics. In aircraft, simulation has been strong in the area of flight control. Modelling and simulation of the hydraulic systems has also a long tradition. The rapid increase in computational power has now come to a point where complete modelling and simulation of all the sub systems in an aircraft is not far away. This means new challenges in dealing with very complex multi domain systems. Of all the systems in an aircraft fluid power systems is one of the most difficult to handle from a numerical point of view. They are characterised by difficulties such as discontinuities, very strong non-linearities, stiff differential equations and a high degree of complexity. A considerable effort has therefore been made to develop methods suitable for simulation of such systems.

Computational Fluid Dynamics CFD is no longer the domain of just specialists. It is also being used by engineers and scientists in many disciplines who are interested in CFD as a tool to investigate other things and not as just an end in itself. The realization of this fact drives developers to produce user-friendly CFD products that automate most of the problem set up and solution process. The CFD++ software suite is a unified-grid, unified-solution, unified-computing CFD simulation capability that was designed from the outset to be effective from the user's perspective. The details are explained in this paper.

In an effort to permit the procurement of more cost-effective military equipment, a method has been developed to perform conceptual studies on combat aircraft, resulting in designs optimized for minimum Life Cycle Cost (LCC). Consequently, the design loop can be considered as being closed, allowing the automated production of a consistent set of cost and performance data for different aircraft solutions. The design engineer can thus make informed, unbiased, design decisions, leading to a more efficient use of shrinking defense budgets. The models and the optimization tool are described, and results of their implementation are presented.

The importance of verification testing in the design process for composite laminated materials aeronautical constructions is discussed, and illustrated by means of two examples drawn from Aeronautical Department (Faculty of Mechanical Engineering, University of Belgrade) experience in the use of composites in a wide variety of structural applications. Laboratory verification testing is conducted at Aeronautical Department on all flight-critical dynamic components in order to determine structural adequacy. In this paper the analysis of behavior by verification testing for a main rotor blade for a light multipurpose helicopter propulsion system and a heavy transport helicopter tail rotor blade of composite laminated materials are given.

Advanced Data Format (ADF) is a portable hierarchical database software library developed by The Boeing Company under contract with NASA [1] and with assistance from industry partners. ADF was designed and built to directly support the CFD General Notation System (CGNS1) project. The CGNS project defines conventions and supplies software to facilitate the exchange of computational fluid dynamics (CFD) data between sites and between applications, and it allows stable archiving of CFD data. CGNS is implemented on the ADF foundation and is focused on the needs of the CFD community. This paper details the design, implementation, use, and future direction of ADF.

The F-22 will be the primary US Air Force air superiority fighter through the first quarter of the 21st century. The F-22 emerged from the Advanced Tactical Fighter (ATF) program. The Concept Definition (CD) phase of the ATF program began in November 1981. ATF Demonstration and Validation (D/V) was initiated in October 1986 with F-22 Engineering and Manufacturing Development (EMD) starting in August 1991. First flight of the EMD F-22 occurred on 7 September, 1997. The F-22 will enter operational service in the year 2005. This paper traces the ATF's developmental history from its earliest beginnings in the 1970s through the CD phase to the formal start of D/V at the end of 1986.

An attempt was made to show that a combination of an upwind thin-layer Navier-Stokes solver with the Johhson-King half-equation algebraic turbulence model offers consistently better results than the standard baseline models, including zero-, one or two equation models. In the present study, in order to improve the robustness, certain compromises have been done on the half-equation model without degrading the accuracy. Implementation has been concentrated on the ONERA M6 wing. Present results demonstrate that the new model performs significantly better on one transonic separated wing flow case than the baseline and other more complicated higher order eddy-viscosity models.

CFD modeling codes, especially those able to analyze general geometries, have traditionally been difficult for users to operate. Unfortunately, this situation often limits the availability of CFD tools to “expert” users and those engineers that have the luxury of going through the CFD learning curve to gain proficiency with a specific technology. A process has been created at Boeing that allows users with only modest experience with CFD analysis to construct and analyze typical transport configurations (e.g., wing/body/strut/nacelle/horizontal and vertical tails) in a single day. The process starts with surface lofts and ends with the required data for engineering decisions. This paper will discuss the design and implementation considerations of such a process and will describe its application to TRANAIR, a full-potential CFD solver with coupled boundary layer for complex geometries. It will also describe the lessons learned and their application to Navier-Stokes solvers.

A fracture mechanics based failure prediction strategy for load-carrying composite structures was proposed. This strategy relies on the knowledge of failure modes and local structural details to predict failure based on coupon level test data. The methodology presented here effectively predicted structural failure of a composite hat stringer based on fracture toughness test data. In addition, ply waviness was identified as a critical factor influencing the delamination failure load. The finite element modeling (FEM) technique was used to model the skin-flange region, which included ply waviness effect. The finite element analysis results were used to calculate total strain energy release rate and its Mode I and Mode II components. The finite element analysis predicted unstable delamination growth for positive waviness angles and stable delamination growth for negative waviness angles.

The payload display design process is intended to assist in designing visual computer interfaces that appropriately support astronauts' interaction with payload displays that fly on missions and yet provide the needed results for the scientists. Standardization of displays will minimize training cost and time while maximizing display usability. This paper proposes a framework for developing displays that integrates human factors design techniques at each step. The fundamental principles upon which the framework is based encompass traditional aspects of human computer interface design, systems design, and human performance.

The Boeing Aero Grid and Paneling System (AGPS) is a programming language with built-in geometry features. Accessible through either a graphical user interface (GUI) or through a command line, AGPS can be used by operators with different levels of experience. Distributed with AGPS are approximately 300,000 lines of macros, or command files, which automate many engineering design and analysis tasks. Most command files were developed to produce inputs to engineering analysis codes such as A502 [1] and TRANAIR [2]. In many cases, command files have been grouped together in AGPS “packages,” which offer users simple menu pick and dialog options to automate entire engineering processes.

This study deals with a simulation tool which enables evaluation of cockpit procedures by activating a crew behavioral model and dynamic environment of aircraft operations. This crew behavioral model employs both physical and cognitive characteristics of human crew members and the tool presents the sequence of their behavior in a form of three dimensional animation. In order to expand the area of application of this tool toward more specific design issues, functions of behavior in non-normal situations were developed. Applicability of this reinforced simulation tool was demonstrated by applying it to examinations of procedures of a research aircraft and identification of test cases of piloted flight simulation. The results of the behavioral simulation were compared with the results of piloted flight simulation.

Making TRANAIR an easier to use wing design tool is an important step toward reducing wing design cycle time. This paper shows the accuracy of TRANAIR in analysis mode for complex configurations with attached flow. This accuracy allows the design part to correctly predict improvements due to design changes. We show the current steps required for the MultiPoint (MP) design version of TRANAIR and the state of refinements toward increasing ease-of-use of this system. Finally, we discuss some of the proposed ways to further improve how the user interacts with the TRANAIR system for MP design.

The design of complex systems, such as commercial aircraft, has drastically changed since the middle 1970's. Budgetary and airline requirements have forced many aerospace companies to reduce the amount of time and monetary investments in future revolutionary concepts and design methods. The current NASA administration has noticed this shift in aviation focus and responded with the “Three Pillars for Success” program. This program is a roadmap for the development of research, innovative ideas, and technology implementation goals for the next 20 years. As a response to this program, the Aerospace Systems Design Laboratory at Georgia Tech is developing methods whereby forecasting techniques will aid in the proper assessment of future vehicle concepts. This method is called Technology Impact Forecasting (TIF). This method is applied to a medium-range, intra-continental, commercial transport concept.